Drainage devices for steam-heated drying cylinders or drums



June 30,1959 A. E. ARMSTRONG, 2,892,264

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Application August 15, 1956, Serial No. 604,235

Claims. (Cl. 34-1'25) Thisinvention relates to improvements in drainage devices or apparatus for steam-heated drying cylinders or drums.

The main objects of this invention are:

First, to provide a structure for removing condensate from steam-heated drying cylinders or drums which is highly efiicient at widely varying cylinder or drum speeds.

Second, to provide a structure having these advantages which, while simple in structure and easily and quickly installed, has an effective dipping or scoop action at speeds below rimming action, or such as to result in so-called rimming of the condensate, at which speeds there is a continuous siphon action, and also at speeds such as permit pooling of condensation, and intermediate speeds resulting in cascading of the condensate.

Third, to provide a structure having the advantage of substantially uniform removal of condensate throughout the length of the drum.

Fourth, to provide a condensate removing device which is well adapted for embodiment in web drying cylinders or drums, for example such as are employed in the drying of webs of paper.

Further objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed outin the claims.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a fragmentary, longitudinal section of a drying cylinder embodying my invention, the condensate removing device being shown in rear elevation by full lines.

Fig. 2 is a transverse section on a line corresponding to line 22 of Fig. l, a rimming layer of condensate being conventionally indicated.

Fig. 3 is an enlarged fragmentary view on a line corresponding to line 33 of Fig. 4.

Fig. 4 is a fragmentary view on a line corresponding to line 4- -4 of Fig. 3, the scoop being further sectioned and partially broken away.

Fig. 5 is a cross sectional view corresponding to that of Fig. 2 illustrating a condition in which the further rotation of the drier is such as to result in pooling of the condensate.

Fig. 6 is a similar view illustrating a condition in which the speed of rotation of the drum is such as to result in cascading.

My invention relates to an apparatus or device for removing condensate from drier cylinders or drums, and is effective when operated at various speeds. This variation in speed results in very great variations in the placement of the condensate within the drum which below speeds in the range of 200 f.p.m. pools or collects in the bottom of the drum and at speeds between this pooling speed and approximately 1,000 f.p.m. there are varying degrees of cascading, the degree of cascading depending upon the speed at which the water is carried on the upwardly moving inner surface of the drier, the degree of cascading depending on the speed.

2,892,264 Patented June 30, 1959 Above 1,000 f.p.m. the water rim is held to the surface of the drum, in a layer of substantially uniform thickness by centrifugal action.

My present invention is designed to effectively remove condensate under these varying operating conditions.

My present invention is an improvement upon the invention of my application for Letters Patent filed September 30, 1953, being Ser. No. 383,153, Patent No. 2,791,038, issued May 7, 1957.

Referring to the drawing, 1 represents a drying cylinder or drum of a paper web drying machine or the like. While drying cylinders or drums vary considerably in structure, the somewhat conventionalized cylinder illustrated discloses a practical embodiment of my invention. Means for driving the drumor cylinder are not illustrated as they vary considerably in commercial installations.

The inner surface 2 of the drum is cylindrical and without internal projections or obstructions which permits uniform distribution of the water from and to the cylinder, that is relative to the web drying portion thereof between the internal shoulders 3. The shoulders are formed by the annular enlargements which facilitate the securing of the heads 4 and 5 by means of bolts 6. The cylinder is provided with a steam inlet 7. The siphon tube 8 is arranged axially of the cylinder and is supported on the bracket 9 projecting into the cylinder. The siphon tube has a radially disposed curved or bowed intake portion 10. The combined discharge and siphon head designated generally by the numeral 11 comprises the parallel side walls 12 between which the rearwardly and outwardly inclined top wall 13 is fixedly secured desirably by welds indicated at 14. The top wall of the scoop terminates closely adjacent to the cylinder wall to provide a slot or slit-like scoop discharge opening 15 desirably of the order of of an inch in width and extending between the side walls. This discharge slit discharges into the siphon tube head chamber 16.

In the embodiment illustrated, the walls of this head chamber are integral with the walls of the scoop. The member forming top wall of the scoop is upwardly offset at 17, at the rear of the scoop discharge 15, and is rearwardly and inwardly inclined to provide the top 18 of the siphon head chamber and then turned outwardly to provide the rear wall 19 of the siphon head chamber. The end walls 12 of the scoop are extended to constitute the end walls of the siphon head chamber. An elbow shaped coupling 20 is fixedly secured at 21 to the top Wall of the head chamber and directed rearwardly to receive the threaded end 22 of the siphon tube inlet section 10.

With this arrangement the condensate water flows without substantial turbulence through the slit-like scoop discharge and through the head chamber to the siphon tube.

In the embodiment illustrated, the siphon tube is engaged with the scoop under spring tension serves to hold the scoop against the wall of the drum for rotation therewith. The curving or bowing of the inlet section of the siphon tube serves the additional function under pooling and cascading conditions of discharging water through a longer stroke than is the case where the inlet section of the siphon tube is straight, as in my said application for Letters Patent.

When the speed of rotation of the drum is below rimming, the scoop acts to pick up water and discharge it through the siphon tube. There is some siphoning action on the water picked up by the scoop. Under rimming conditions, the condensate is uniformly distributed on the wall of the cylinder or drum and the device acts as a siphoning device.

With the scoop discharge of approximately of an inch in width, and the scoop approximately 14 inches in length, the flow through the slit at its capacity is approximately that of a one inch siphon tube. This proportioning is a desirable feature and results in high efficiency under rimming conditions and also under pooling and cascading conditions. This highly effective removal of condensate also results in a very substantial saving in power required to drive the drums.

The forming of the cylinder without internal obstruction to the gravitational and centrifugal distribution of condensate from end to end thereof, not only facilitates removal thereof under varying speed conditions but also results in substantially uniform drying temperatures, eliminating spotted drying. Further, the walls of the cylinder may be relatively thin, thereby increasing its drying or heat transfer-capacity.

The device of my invention is not only simple in structure, but it is very. easily installed and no screws or bolts or other means for securing to the cylinder wall are required.

I have illustrated and described my invention in a highly practical commercial embodiment thereof. I have not attempted to illustrate or describe the same in other embodiments or adaptations, as it is believed that this disclosure will enable those skilled in the art to embody or adapt my invention as may be desired.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent is:

1. In combination with a rotatable drying drum having a steam supply connection, the inner surface of the drum being cylindrical and without internal projection portion affecting the gravitational and centrifugal distribution of the condensate from end to end thereof, a siphon tube having a curved radially disposed intake portion, a scoop opening in the direction of rotation of the drum and rotating therewith, the inner side of the drum constituting the bottom of the scoop, the scoop comprising side walls and a rearwardly and outwardly inclincd top wall terminating closely adjacent to the inner surface of the drum and coacting therewith to provide a slit-like discharge opening extending from side wall to side wall, the top wall of the scoop being extended and offset inwardly to the rear of the slit defining portion thereof, and thence inwardly inclined and terminating in an outwardly turned portion constituting the rear wall of a scoop discharge chamber, the side walls of the scoop being extended to constitute side walls for the discharge chamber, and an elbowed siphon tube coupling mounted on and opening through the top of said discharge chamber centrally thereof, said curved intake portion of said siphon tube being engaged with said coupling member under spring tension and acting to springably urge said scoop against the drum wall.

2. In combination with a rotatable drying drum having a steam supply connection, the inner surface of the drum being cylindrical and without internal projection portion affecting the gravitational and centrifugal distribution of the condensate from end to end thereof, a siphon tube having a curved radially disposed intake portion, a scoop opening in the direction of rotation of the drum and rotating therewith, the inner side of the drum constituting the bottom of the scoop, the scoop comprising side walls and a rearwardly and outwardly inclined top wall terminating closely adjacent to the inner surface of the drum and coacting therewith to provide a slit-like discharge opening extending from side wall to side wall, said scoop having an elongated chambered siphon tube head portion into which said slit-like opening discharges, said curved intake portion of said siphon tube being engaged with said head under spring tension and acting to springably urge said scoop against the drum wall.

3. The combination with a rotatable drying drum having a steam supply connection, the inner surface of the drum being cylindrical and without obstructions affecting the gravitational and centrifugal distribution of condensate from end to end thereof, of a siphon tube, a scoop opening in the direction of the rotation of the drum and rotating therewith, the inner side of the drum constituting the bottom of the scoop, the scoop comprising side walls and a rearwardly and outwardly inclined top wall terrninating adjacent to the inner surface of the drum and coacting therewith to provide a slit-like discharge opening, said scoop having an elongated chambered siphon tube head into which said slit-like opening discharges, said siphon tube being rearwardly bowed and connected to said head under springable stress and acting to thrustingly support the scoop against the wall of the drum.

4. The combination with a rotatable drying drum having a steam supply connection, the inner surface of the drum being cylindrical and without obstructions affecting the gravitational and centrifugal distribution of condensate from end to end thereof, of a rearwardly bowed siphon tube, a scoop opening in the direction of the rotation of the drum and rotating therewith, the inner side of the drum constituting the bottom of the scoop, the scoop comprising side walls, and a rearwardly and outwardly inclined top wall terminating adjacent to the inner surface of the drum and coacting therewith to provide a slit-like discharge opening, said scoop having an elongated chambered head into which said slit-like opening discharges, said siphon tube being connected to said head in rearwardly bowed relation to the scoop and acting to yieldingly urge .the scoop side walls into supported engagement with the cylinder wall.

5. In combination with a rotatable drying drum having a steam supply connection, the inner surface of the drum being cylindrical and without internal projection portion affecting the gravitational and centrifugal distribution of the condensate from end to end thereof, a siphon tube having a radially disposed intake'portion, a scoop opening in the direction of rotation of the drum and rotating therewith, the inner side of the drum constituting the bottom of the scoop, the scoop comprising side walls and rearwardly and outwardly inclined top wall terminating closely adjacent to the inner surface of the drum and coacting therewith to provide a slit-like discharge opening and extending from side wall to side wall, said scoop having an elongated discharge chamber into which said slit opens, said intake portion of said siphon tube being bowed and acting to springably support said scoop against the drum wall.

References Cited in the file of this patent UNITED STATES PATENTS 267,666 Brigham Nov. 21, 1882 977,376 Dodge Nov. 29, 1910 2,677,898 Ohlson et al. May 11, 1954 2,791,038 Armstrong May 7, 1957 

